Organic light-emitting diode luminaires

ABSTRACT

There is provided an organic light-emitting diode luminaire. The luminaire includes a patterned first electrode, a second electrode, and an electroluminescent layer therebetween. The electroluminescent layer includes:
         a host material capable of electroluminescence having an emission color that is blue;   a first electroluminescent dopant having an emission color that is green; and   a second electroluminescent dopant having an emission color that is in the red/orange region.
 
The additive mixing of all the emitted colors results in an overall emission of white light.

RELATED APPLICATION DATA

This application claims priority under 35 U.S.C. §119(e) from U.S.Provisional Application Nos. 61/255920 filed on Oct. 29, 2009 and61/362403 filed on Jul. 8, 2010, which is incorporated by referenceherein in its entirety.

BACKGROUND INFORMATION

1. Field of the Disclosure

This disclosure relates in general to organic light-emitting diode(“OLED”) luminaires. It also relates to a process for making suchdevices.

2. Description of the Related Art

Organic electronic devices that emit light are present in many differentkinds of electronic equipment. In all such devices, an organic activelayer is sandwiched between two electrodes. At least one of theelectrodes is light-transmitting so that light can pass through theelectrode. The organic active layer emits light through thelight-transmitting electrode upon application of electricity across theelectrodes. Additional electroactive layers may be present between theelectroluminescent layer and the electrode(s).

It is well known to use organic electroluminescent compounds as theactive component in light-emitting diodes. Simple organic molecules,such as anthracene, thiadiazole derivatives, and coumarin derivativesare known to show electroluminescence. In some cases these smallmolecule materials are present as a dopant in a host material to improveprocessing and/or electronic properties.

OLEDs emitting different colors, usually red, green, and blue, can beused in subpixel units to emit white light. OLEDs emitting white lightcan be used for lighting applications.

There is a continuing need for new OLED structures and processes formaking them for lighting applications.

SUMMARY

There is provided an organic light-emitting diode luminaire comprising afirst electrode, a second electrode, and an electroluminescent layertherebetween, the electroluminescent layer comprising:

-   -   a host material capable of electroluminescence having an        emission color that is blue;    -   a first electroluminescent dopant having an emission color that        is green; and    -   a second electroluminescent dopant having an emission color that        is in the red/orange region;        wherein the additive mixing of the emitted colors results in an        overall emission of white light.

There is also provided a process for making an OLED luminaire,comprising:

providing a substrate having a first electrode thereon;

depositing a liquid composition comprising a liquid medium havingdispersed therein a host material which is capable ofelectroluminescence having blue emission color, a firstelectroluminescent dopant having green emission color, and a secondelectroluminescent material having emission color in the red/orangeregion;

drying the deposited composition to form an electroluminescent layer;and

forming a second electrode overall.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated in the accompanying figures to improveunderstanding of concepts as presented herein.

FIG. 1( a) is an illustration of one prior art white light-emittingdevice.

FIG. 1( b) is an illustration of another prior art white light-emittingdevice.

FIG. 2 is an illustration of an OLED luminaire.

Skilled artisans appreciate that objects in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the objects in the figures may beexaggerated relative to other objects to help to improve understandingof embodiments.

DETAILED DESCRIPTION

Many aspects and embodiments have been described above and are merelyexemplary and not limiting. After reading this specification, skilledartisans appreciate that other aspects and embodiments are possiblewithout departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments willbe apparent from the following detailed description, and from theclaims. The detailed description first addresses Definitions andClarification of Terms followed by the Luminaire, Materials, the Processand finally Examples.

1. Definitions and Clarification of Terms

Before addressing details of embodiments described below, some terms aredefined or clarified.

As used herein, the term “alkoxy” refers to the group RO—, where R is analkyl.

The term “alkyl” is intended to mean a group derived from an aliphatichydrocarbon having one point of attachment, and includes a linear, abranched, or a cyclic group. The term is intended to includeheteroalkyls. The term “hydrocarbon alkyl” refers to an alkyl grouphaving no heteroatoms. In some embodiments, an alkyl group has from 1-20carbon atoms.

The term “aryl” is intended to mean a group derived from an aromatichydrocarbon having one point of attachment. The term “aromatic compound”is intended to mean an organic compound comprising at least oneunsaturated cyclic group having delocalized pi electrons. The term isintended include heteroaryls. The term “hydrocarbon aryl” is intended tomean aromatic compounds having no heteroatoms in the ring. In someembodiments, an aryl group has from 3-30 carbon atoms.

The term “blue” refers to an emission with color coordinates ofx=0.12-0.14 and y=0.15-0.21.

The term “color coordinates” refers to the x- and y-coordinatesaccording to the C.I.E. chromaticity scale (Commission Internationale deL'Eclairage, 1931).

The term “CRI” refers to the CIE Color Rendering Index. It is aquantitative measure of the ability of a light source to reproduce thecolors of various objects faithfully in comparison with an ideal ornatural light source. A reference source, such as black body radiation,is defined as having a CRI of 100.

The term “dopant” is intended to mean a material, within a layerincluding a host material, that changes the wavelength(s) of radiationemission of the layer compared to the wavelength(s) of radiationemission of the layer in the absence of such material.

The term “drying” is intended to mean the removal of at least 50% byweight of the liquid medium; in some embodiments, at least 75% by weightof the liquid medium. A “partially dried” layer is one in which someliquid medium remains. A layer which is “essentially completely dried”is one which has been dried to an extent such that further drying doesnot result in any further weight loss.

The term “electroluminescence” refers to the emission of light from amaterial in response to an electric current passed through it.“Electroluminescent” refers to a material or layer that is capable ofelectroluminescence.

The prefix “fluoro” indicates that one or more available hydrogen atomshave been replaced with a fluorine atom.

The term “green” refers to an emission with color coordinates ofx=0.20-0.30 and y=0.55-0.65.

The prefix “hetero” indicates that one or more carbon atoms have beenreplaced with a different atom. In some embodiments, the different atomis N, O, or S.

The term “host material” is intended to mean a material, usually in theform of a layer, to which an electroluminescent dopant may be added andfrom which the dopant will be emissive. The host material is present inhigher concentration than the sum of all the dopant concentrations.

The term “liquid composition” is intended to mean a liquid medium inwhich a material is dissolved to form a solution, a liquid medium inwhich a material is dispersed to form a dispersion, or a liquid mediumin which a material is suspended to form a suspension or an emulsion.

The term “liquid medium” is intended to mean a liquid material,including a pure liquid, a combination of liquids, a solution, adispersion, a suspension, and an emulsion. Liquid medium is usedregardless whether one or more solvents are present.

The term “luminaire” refers to a lighting panel, and may or may notinclude the associated housing and electrical connections to the powersupply.

The term “orange” refers to an emission with color coordinates ofx=0.56-0.60 and y=0.39-0.43.

The term “overall emission” as it refers to a luminaire, means theperceived light output of the luminaire as a whole.

The term “red” refers to an emission with color coordinates ofx=0.66+/−0.02 and y=0.30+/−0.02.

The term “red-orange” refers to an emission with color coordinates ofx=0.62+/−0.02 and y=0.35+/−0.03.

The term “red/orange region” refers to an emission with colorcoordinates of x=0.56-0.68 and y=0.28-0.43.

The term “silyl” refers to the group R₃Si—, where R is H, D, C1-20alkyl, fluoroalkyl, or aryl. In some embodiments, one or more carbons inan R alkyl group are replaced with Si. In some embodiments, the silylgroups are (hexyl)₂Si(CH₃)CH₂CH₂Si(CH₃)₂— and[CF₃(CF₂)₆CH₂CH₂]₂Si(CH₃)—.

The term “white light” refers to light perceived by the human eye ashaving a white color.

All groups may be unsubstituted or substituted. In some embodiments, thesubstituents are selected from the group consisting of D, halide, alkyl,alkoxy, aryl, aryloxy, and fluoroalkyl.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of theelements use the “New Notation” convention as seen in the CRC Handbookof Chemistry and Physics, 81^(st) Edition (2000-2001).

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present invention, suitablemethods and materials are described below. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

To the extent not described herein, many details regarding specificmaterials, processing acts, and circuits are conventional and may befound in textbooks and other sources within the organic light-emittingdiode display, photodetector, photovoltaic, and semiconductive memberarts.

2. The Luminaire

It is known to have white light-emitting layers in which emissive layersof different colors are stacked on top of each other between an anodeand a cathode. Two exemplary prior art devices are shown in FIG. 1. InFIG. 1 a, the anode 3 and the cathode 11 have a blue light-emittinglayer 6, a green light-emitting layer 9, and a red light-emitiing layer10 stacked between them on substrate 2. On either side of theelectroluminescent layers are hole transport layers 4, electrontransport layers 8. there are also hole blocking layers 7 and electronblocking layers 5. In FIG. 1 b, the substrate 2, anode 3, hole transportlayer 4, electron transport layer 8 and cathode 11 are present as shown.Light-emitting layer 12 is a combination of yellow and redlight-emitters in a host material. Light-emitting layer 13 is a bluelight-emitting in a host material. Layer 14 is an additional layer ofhost material.

The luminaire described herein has a single light-emitting layer ratherthan multiple layers in a stacked configuration.

The luminaire has a first electrode, a second electrode, and anelectroluminescent layer therebetween. The electroluminescent layercomprises a host material capable of electroluminescence having blueemission color, a first electroluminescent dopant having green emissioncolor, and a second electroluminescent dopant having emission color inthe red/orange region. The additive mixing of the emitted colors resultsin an overall emission of white light. At least one of the electrodes isat least partially transparent to allow for transmission of thegenerated light.

One of the electrodes is an anode, which is an electrode that isparticularly efficient for injecting positive charge carriers. In someembodiments, the first electrode is an anode. In some embodiments, theanode is at least partially transparent. The other electrode is acathode, which is an electrode that is particularly efficient forinjecting electrons or negative charge carriers.

The electroluminescent materials can be chosen based on high luminousefficiency instead, as long as high CRI values are obtainable.

In some embodiments, the OLED luminaire further comprises additionallayers. In some embodiments, the OLED luminaire further comprises one ormore charge transport layers. The term “charge transport,” whenreferring to a layer, material, member, or structure is intended to meansuch layer, material, member, or structure facilitates migration of suchcharge through the thickness of such layer, material, member, orstructure with relative efficiency and small loss of charge. Holetransport layers facilitate the movement of positive charges; electrontransport layers facilitate the movements of negative charges. Althoughelectroluminescent materials may also have some charge transportproperties, the term “charge transport layer, material, member, orstructure” is not intended to include a layer, material, member, orstructure whose primary function is light emission.

In some embodiments, the OLED luminaire further comprises one or morehole transport layers between the electroluminescent layer and theanode. In some embodiments, the OLED luminaire further comprises one ormore electron transport layers between the electroluminescent layer andthe cathode.

In some embodiments, the OLED luminaire further comprises a holeinjection layer between the anode and a hole transport layer. The term“hole injection layer” or “hole injection material” is intended to meanelectrically conductive or semiconductive materials. The hole injectionlayer may have one or more functions in an organic electronic device,including but not limited to, planarization of the underlying layer,charge transport and/or charge injection properties, scavenging ofimpurities such as oxygen or metal ions, and other aspects to facilitateor to improve the performance of the organic electronic device.

One example of an OLED luminaire is illustrated in FIG. 2. OLEDluminaire 100 has substrate 110 with anode 120 and bus lines 330. On theanode are the organic layers: hole injection layer 130, hole transportlayer 140, and the electroluminescent layer 150. The electron transportlayer 160 and cathode 170 are applied overall.

The OLED luminaire can additionally be encapsulated to preventdeterioration due to air and/or moisture. Various encapsulationtechniques are known. In some embodiments, encapsulation of large areasubstrates is accomplished using a thin, moisture impermeable glass lid,incorporating a desiccating seal to eliminate moisture penetration fromthe edges of the package. Encapsulation techniques have been describedin, for example, published US application 2006-0283546.

There can be different variations of OLED luminaires which differ onlyin the complexity of the drive electronics (the OLED panel itself is thesame in all cases). The drive electronics designs can still be verysimple.

3. Materials

The electroluminescent layer of the device comprises a host materialcapable of electroluminescence having an emission color that is blue, afirst electroluminescent dopant having an emission color that is green,and a second electroluminescent dopant having an emission color that isin the red/orange region. In some embodiments, the electroluminescentlayer consists essentially of the host material, the first dopant, andthe second dopant.

a. Host

The host of the present invention is an electroluminescent materialhaving blue emission color. The host is selected so that emission can beachieved from the host and the two dopants. For example, the host shouldhave a HOMO-LUMO gap that is greater than the gap for each of the twoelectroluminescent dopants. In addition, the triplet energy of the hostshould be high enough so that it does not quench the emission from theorganometallic electroluminescent materials.

Any type of electroluminescent (“EL”) material can be used as the hostso long as it has the appropriate electronic properties. Types of ELhost materials, include, but are not limited to, small molecule organicluminescent compounds, luminescent metal complexes, conjugated polymers,and mixtures thereof. In some embodiments, a combination of two or moreelectroluminescent materials having blue emission color are present ashosts.

In some embodiments, the host material with blue emission color is anorganometallic complex of Ir. In some embodiments, the organometallic Ircomplex is a tris-cyclometallated complex having the formula IrL₃ or abis-cyclometallated complex having the formula IrL₂Y, where Y is amonoanionic bidentate ligand and L has a formula selected from the groupconsisting of Formula L-1 through Formula L-12:

where:

-   -   R¹ through R⁸ are the same or different and are selected from        the group consisting of H, D, electron-donating groups, and        electron-withdrawing groups, and R⁹ is H, D or alkyl; and    -   * represents a point of coordination with Ir.

The emitted color is tuned by the selection and combination ofelectron-donating and electron-withdrawing substituents. In addition,the color is tuned by the choice of Y ligand in the bis-cyclometallatedcomplexes. Shifting the color to shorter wavelengths is accomplished by(a) selecting one or more electron-donating substituents for R¹ throughR⁴; and/or (b) selecting one or more electron-withdrawing substituentsfor R⁵ through R⁸; and/or (c) selecting a bis-cyclometallated complexwith ligand Y-2 or Y-3, shown below. Conversely, shifting the color tolonger wavelengths is accomplished by (a) selecting one or moreelectron-withdrawing substituents for R¹ through R⁴; and/or (b)selecting one or more electron-donating substituents for R⁵ through R⁸;and/or (c) selecting a bis-cyclometallated complex with ligand Y-1,shown below. Examples of electron-donating substituents include, but arenot limited to, alkyl, silyl, alkoxy, and dialkylamino. Examples ofelectron-withdrawing substituents include, but are not limited to, F,CN, fluoroalkyl, alkoxy, and fluoroalkoxy. Substituents may also bechosen to affect other properties of the materials, such as solubility,air and moisture stability, emissive lifetime, and others.

In some embodiments of Formulae L-1 through L-12, at least one of R¹through R⁴ is an electron-donating substituent. In some embodiments ofFormula L-1, at least one of R⁵ through R⁸ is an electron-withdrawingsubstituent.

In some embodiments of Formulae L-1 through L-12:

-   -   R¹ is H, D, F, or alkyl;    -   R² is H, D or alkyl;    -   R³═H, D, F, alkyl, OR¹⁰, NR¹⁰ ₂;    -   R⁴═H or D;    -   R⁵═H, D or F;    -   R⁶═H, D, CN, F, aryl, fluoroalkyl, or diaryloxophosphinyl;    -   R⁷═H, D, F, alkyl, aryl, or diaryloxophosphinyl;    -   R⁸═H, D, CN, alkyl, fluoroalkyl;    -   R⁹═H, D, aryl or alkyl;    -   R¹⁰=alkyl, where adjacent R¹⁰ groups can be joined to form a        saturated ring; and    -   * represents a point of coordination with Ir.

In some embodiments, Y is selected from the group consisting of Y-1, Y-2and Y-3

wherein:

-   -   R¹¹ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl;    -   R¹² is H, D or F; and    -   R¹³ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl.

In some embodiments, the alkyl and fluoroalkyl groups have 1-5 carbonatoms. In some embodiments, the alkyl group is methyl. In someembodiments, the fluoroalkyl group is trifluoromethyl. In someembodiments, the aryl group is a heteroaryl. In some embodiments, thearyl group is a phenyl group having one or more substituents selectedfrom the group consisting of F, CN, and CF₃. In some embodiments, thearyl group is selected from the group consisting of o-fluorophenyl,m-fluorophenyl, p-fluorophenyl, p-cyanophenyl, and3,5-bis(trifluoromethyl)phenyl. In some embodiments, thediaryloxophosphinyl group is diphenyloxophosphinyl.

In some embodiments, the organometallic Ir complex having blue emissioncolor has the formula IrL₃. In some embodiments, the complex has theformula IrL₃, where L is Formula L-1, R⁵ is H or D and R⁶ is F, aryl,heteroaryl, or diaryloxophosphinyl. In some embodiments, R⁵ is F and R⁶is H or D. In some embodiments, two or more of R⁵, R⁶, R⁷ and R⁸ are F.

In some embodiments, the organometallic Ir complex having blue emissioncolor has the formula IrL₂Y. In some embodiments, the complex has theformula IrL₂Y, where L is Formula L-1, R¹, R², R⁶ and R⁸ are H or D. Insome embodiments, R⁵ and R⁷ are F.

Examples of organometallic Ir complexes having blue emission colorinclude, but are not limited to:

b. Dopants

Any type of electroluminescent (“EL”) material can be used as a dopant,including, but not limited to, small molecule organic luminescentcompounds, luminescent metal complexes, conjugated oligomers, conjugatedpolymers, and mixtures thereof.

In some embodiments, the first electroluminescent dopant with greenemission color is an organometallic complex of Ir. In some embodiments,the organometallic Ir complex is a tris-cyclometallated complex havingthe formula IrL₃ or a bis-cyclometallated complex having the formulaIrL₂Y, where Y is a monoanionic bidentate ligand and L has a formulaselected from the group consisting of L-1, L-3 through L-7, and L-9through L-17:

where:

-   -   R¹ through R⁸ are the same or different and are selected from        the group consisting of H, D, electron-donating groups, and        electron-withdrawing groups, and R⁹ is H, D or alkyl; and    -   * represents a point of coordination with Ir.

As discussed above, the emitted color is tuned by the selection andcombination of electron-donating and electron-withdrawing substituentsand the selection of the Y ligand.

In some embodiments, of Formulae L-1, L-3 through L-7, and L-9 throughL-17:

-   -   R¹═H, D or F;    -   R²═H, D, F, or alkyl;    -   R³═H, D or diarylamino;    -   R⁴═H, D or F;    -   R⁵═H, D or alkyl, or R⁴ and R⁵ may be joined together to form a        6-membered aromatic ring;    -   R⁶═H, D, F, aryl, fluoroalkoxy, N-carbazolyl,        diphenyl-N-carbazolyl or

-   -   R⁷═H, D, F, fluoroalkoxy, N-carbazolyl, or        diphenyl-N-carbazolyl;    -   R⁸═H, D or F; and    -   R⁹═H, D, aryl or alkyl,    -   where the asterisk represents the point of attachment.

In some embodiments, Y is selected from the group consisting of Y-1, Y-2and Y-3

wherein:

-   -   R¹¹ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl;    -   R¹² is H, D or F; and    -   R¹³ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl.

In some embodiments, the alkyl and fluoroalkyl groups have 1-5 carbonatoms. In some embodiments, the alkyl group is methyl. In someembodiments, the fluoroalkyl group is trifluoromethyl. In someembodiments, the aryl group is a heteroaryl. In some embodiments, thearyl group is N-carbazolyl or diphenyl-N-carbazolyl. In someembodiments, the aryl group is phenyl or substituted phenyl. In someembodiments, the aryl group is a phenyl group having one or moresubstituents selected from the group consisting of F, CN, alkyl, andfluoroalkyl. In some embodiments, the aryl group is selected from thegroup consisting of p-(C₁₋₅)alkylphenyl, o-fluorophenyl, m-fluorophenyl,p-fluorophenyl, p-cyanophenyl, and 3,5-bis(trifluoromethyl)phenyl.

In some embodiments, the organometallic Ir complex having green emissioncolor has the formula IrL₃ where L has Formula L-1. In some embodimentsof Formula Ia, R² is H, D or methyl and R¹, R³ and R⁴ are H or D. Insome embodiments, R⁶ is selected from the group consisting of phenyl,substituted phenyl, N-carbazolyl, and diphenyl-N-carbazolyl.

Examples of organometallic Ir complexes with green emission colorinclude, but are not limited to

The second electroluminescent dopant has emission color in thered/orange region. In some embodiments, the second dopant has redemission color. In some embodiments, the second dopant has red-orangeemission color. In some embodiments, the second dopant has orangeemission color.

In some embodiments, the second electroluminescent dopant has redemission color and is an organometallic complex of Ir. In someembodiments, the organometallic Ir complex is a tris-cyclometallatedcomplex having the formula IrL₃ or a bis-cyclometallated complex havingthe formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has aformula selected from the group consisting of Formula L-18, L-19 andL-20:

where:

-   -   R¹ through R⁶ and R²¹ through R³⁰ are the same or different and        are selected from the group consisting of H, D,        electron-donating groups, and electron-withdrawing groups; and    -   * represents a point of coordination with Ir.

As discussed above, the emitted color is tuned by the selection andcombination of electron-donating and electron-withdrawing substituents,and by the selection of the Y ligand in the bis-cyclometallatedcomplexes. Shifting the color to shorter wavelengths is accomplished by(a) selecting one or more electron-donating substituents for R¹ throughR⁴ or R²¹ through R²⁶; and/or (b) selecting one or moreelectron-withdrawing substituents for R⁵ through R⁶ or R²⁷ through R³⁰;and/or (c) selecting a bis-cyclometallated complex with ligand Y-2 orY-3. Conversely, shifting the color to longer wavelengths isaccomplished by (a) selecting one or more electron-withdrawingsubstituents for R¹ through R⁴ or R²¹ through R²⁶; and/or (b) selectingone or more electron-donating substituents for R⁵ through R⁶ or R²⁷through R³⁰; and/or (c) selecting a bis-cyclometallated complex withligand Y-1.

In some embodiments of Formulae L-18 through L-20:

-   -   R¹ through R⁴ and R²¹ through R²⁶ are the same or different and        are H, D, alkyl, alkoxy, or silyl, or R¹ and R², R² and R³ or R³        and R⁴ in ligand L-18, or R²³ and R²⁴ or R²⁴ and R²⁵ in ligand        L-19 and L-20 can be joined together to form a hydrocarbon ring        or hetero ring;    -   R²⁷═H, D, F, alkyl, silyl, or alkoxy;    -   R²⁸═H, D, CN, F, alkyl, fluoroalkyl, fluoroalkoxy, silyl, or        aryl; and    -   R²⁹═F, CN, alkyl, silyl, alkoxy, fluoroalkoxy, or aryl    -   R³⁹═H, D, F, CN, fluoroalkyl, fluoroalkoxy, alkyl, or silyl.

In some embodiments, Y is selected from the group consisting of Y-1, Y-2and Y-3

wherein:

-   -   R¹¹ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl;    -   R¹² is H, D or F; and    -   R¹³ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl.

In some embodiments of the formulae, the alkyl, fluoroalkyl, alkoxy andfluoroalkoxy groups have 1-5 carbon atoms. In some embodiments, thealkyl group is methyl. In some embodiments, the fluoroalkyl group istrifluoromethyl. In some embodiments, the aryl group is a heteroaryl. Insome embodiments, the aryl group is N-carbazolyl or N-carbazolylphenyl.In some embodiments, the aryl group is phenyl, substituted phenyl,biphenyl, or substituted biphenyl. In some embodiments, the aryl groupis selected from the group consisting of phenyl, biphenyl,p-(C₁₋₅)alkylphenyl, and p-cyanophenyl.

In some embodiments of Formula L-18, all the R are H or D.

In some embodiments of Formula L-19, R²¹, R²², R²³, R²⁴, R²⁵, and R²⁶are H or D. In some embodiments, at least one of R²⁷, R²⁸, and R²⁹ isselected from the group consisting of methyl, methoxy, and t-butyl.

In some embodiments of Formula L-20, R²¹, R²², R²³, R²⁴, R²⁵, and R²⁶are H or D. In some embodiments, R²⁹ is aryl.

In some embodiments, the complex having red emission color is abis-cyclometallated complex with ligand Y-1. In some embodiments, R¹¹ isselected from methyl and butyl and R¹² is H or D.

Examples of ligand L-19 include, but are not limited to, those given inTables 1 and 2 below. Examples of ligand L-20 include, but are notlimited to, those given in Table 3 below.

TABLE 1 Ligand L-19. Ligand R²⁸ R²⁹ R-1  H H R-2  H CN R-3  CN H R-4  H

R-5 

H R-6  H

R-7 

H R-8  H

R-9 

H R-10 H

R-11

H R-12 H

R-13

H R-14 H

R-15

H R-16 H t-butyl R-17 CH₃ F R-18 H OCH₃ R-19 H OCHF₂where R²¹ through R²⁷, and R³⁰ are H

TABLE 2 Ligand L-19 Ligand R²³ R²⁴ R²⁵ R²⁶ R²⁷ R²⁸ R²⁹ R-20 H H H H H Ht-Bu R-21 Me H H H H H H R-22 H Me H H H H H R-23 H H Me H H H H R-24 HH H Me H H H R-25 Me H H H H t-Bu H R-26 H Me H H H t-Bu H R-27 H H Me HH t-Bu H R-28 H H H Me H t-Bu H R-29 Me H H H H H t-Bu R-30 H Me H H H Ht-Bu R-31 H H Me H H H t-Bu R-32 H H H Me H H t-Bu R-33 H Me Me H H Ht-Bu R-34 H Me Me H H H H R-35 Me Me H H H H H R-36 Me H Me H H H H R-37OMe H H H H H H R-38 H OMe H H H H H R-39 H H OMe H H H H R-40 OMe H H HH t-Bu H R-41 OMe Me H H H H H R-42 SiMe₃ H H H H H H R-43 H SiMe₃ H H HH H R-44 H H SiMe₃ H H H H R-45

H H H H H R-46 H H Me H H H OMe R-47 H H Me H OMe H OMe R-48 H H Me H HH OMe R-49 H Me Me H H H OMe R-50 H H Me H H H t-Bu R-51 H OMe H H H Ht-Buwhere Me=methyl, t-Bu=t-butyl, and R³⁰═H

TABLE 3 Ligand L-20 Ligand R²¹ R²⁷ R²⁸ R²⁹ R-52 H H H t-Bu R-53 H H Hphenyl R-54 Me H H t-Bu R-55 Me H H phenyl R-56 Me H H biphenyl R-57 MeH Me phenylwhere Me=methyl, t-Bu=t-butyl, R²²-R²⁶ and R³⁰═H

Examples of organometallic Ir complexes having red emission colorinclude, but are not limited to:

In some embodiments, the second electroluminescent dopant has red-orangeemission color and is an organometallic complex of Ir. In someembodiments, the organometallic Ir complex is a tris-cyclometallatedcomplex having the formula IrL₃ or a bis-cyclometallated complex havingthe formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has aformula selected from the group consisting of Formula L-18, L-19, L-20and L-21:

where:

-   -   R¹ through R⁶ and R²¹ through R³⁰ are the same or different and        are selected from the group consisting of H, D,        electron-donating groups, and electron-withdrawing groups; and    -   * represents a point of coordination with Ir.

As discussed above, the emitted color is tuned by the selection andcombination of electron-donating and electron-withdrawing substituents,and by the selection of the Y ligand in the bis-cyclometallatedcomplexes. Shifting the color to shorter wavelengths is accomplished by(a) selecting one or more electron-donating substituents for R¹ throughR⁴ or R²¹ through R²⁶; and/or (b) selecting one or moreelectron-withdrawing substituents for R⁵ through R⁶ or R²⁷ through R³⁰;and/or (c) selecting a bis-cyclometallated complex with ligand Y-2 orY-3. Conversely, shifting the color to longer wavelengths isaccomplished by (a) selecting one or more electron-withdrawingsubstituents for R¹ through R⁴ or R²¹ through R²⁶; and/or (b) selectingone or more electron-donating substituents for R⁵ through R⁶ or R²⁷through R³⁰; and/or (c) selecting a bis-cyclometallated complex withligand Y-1.

In some embodiments of Formulae L-18 through L-21:

-   -   R¹ through R⁴ and R²¹ through R²⁶ are the same or different and        are H, D, alkyl, silyl, or alkoxy, or R¹ and R², R² and R³ or R³        and R⁴ in ligand L-18, or R²³ and R²⁴ or R²⁴ and R²⁵ in ligand        L-19 and L-20, or R²³ and R²⁴, R²⁴ and R²⁵, or R²⁵ and R²⁶ in        Ligand L-21 can be joined together to form a hydrocarbon ring or        hetero ring;    -   R²⁷═H, D, alkyl, or silyl;    -   R²⁸═H, D, alkyl, or silyl;    -   R²⁹═H, D, alkyl, silyl, alkoxy, fluoroalkoxy, or aryl; and    -   R³⁰═H, D, alkyl, or silyl.

In some embodiments, Y is selected from the group consisting of Y-1, Y-2and Y-3

wherein:

-   -   R¹¹ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl;    -   R¹² is H, D or F; and    -   R¹³ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl.

In some embodiments of the formulae, the alkyl, fluoroalkyl, alkoxy andfluoroalkoxy groups have 1-5 carbon atoms. In some embodiments, thealkyl group is methyl. In some embodiments, the alkoxy group is methoxy.In some embodiments, the fluoroalkyl group is trifluoromethyl . In someembodiments, the aryl group is phenyl.

In some embodiments, L=L-19 and the complex has the formula IrL₃. Insome embodiments, L=L-20 and the complex has the formula IrL₂Y or IrL₃.In some embodiments, L=L-19 and the complex has the formula IrL₂Y.

In some embodiments of L-19, at least one of R²³ through R²⁶ is alkoxy.In some embodiments of L-19, at least one of R²⁷ through R³⁰ is alkoxyor fluoroalkoxy.

In some embodiments, L=L-20 R²³ through R²⁶ are H or D. In someembodiments of L-20, at least one of R²¹ and R²⁹ is a C₁₋₅ alkyl group.

In some embodiments of L-21, R²³ through R²⁶ are H or D. In someembodiments of L-21, at least one of R²¹ and R²⁹ is a C₁₋₅ alkyl group.In some embodiments of L-21, at least one of R²⁷ through R³⁰ is a C₁₋₅alkoxy or fluoroalkoxy group.

Examples of organometallic Ir complexes having red-orange emission colorinclude, but are not limited to:

In some embodiments, the second electroluminescent dopant has orangeemission color and is an organometallic complex of Ir. In someembodiments, the organometallic Ir complex is a tris-cyclometallatedcomplex having the formula IrL₃ or a bis-cyclometallated complex havingthe formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has aformula selected from the group consisting of Formula L-18, L-19, L-20and L-21:

where:

-   -   R¹ through R⁶ and R²¹ through R³⁰ are the same or different and        are selected from the group consisting of H, D,        electron-donating groups, and electron-withdrawing groups; and    -   * represents a point of coordination with Ir.

As discussed above, the emitted color is tuned by the selection andcombination of electron-donating and electron-withdrawing substituents,and by the selection of the Y ligand in the bis-cyclometallatedcomplexes. Shifting the color to shorter wavelengths is accomplished by(a) selecting one or more electron-donating substituents for R¹ throughR⁴ or R²¹ through R²⁶; and/or (b) selecting one or moreelectron-withdrawing substituents for R⁵ through R⁶ or R²⁷ through R³⁰;and/or (c) selecting a bis-cyclometallated complex with ligand Y-2 orY-3. Conversely, shifting the color to longer wavelengths isaccomplished by (a) selecting one or more electron-withdrawingsubstituents for R¹ through R⁴ or R²¹ through R²⁶; and/or (b) selectingone or more electron-donating substituents for R⁵ through R⁶ or R²′through R³⁰; and/or (c) selecting a bis-cyclometallated complex withligand Y-1.

In some embodiments of Formulae L-18 through L-21:

-   -   R¹ through R⁴ and R²¹ through R²⁶ are the same or different and        are H, D, alkyl, or silyl, or R¹ and R², R² and R³ or R³ and R⁴        in ligand L-18, or R¹⁶ and R¹⁷ or R¹⁷ and R¹⁸ in ligand L-19 and        L-20, or R¹⁶ and R¹⁷, R¹⁷ and R¹⁸, or R¹⁸ and R¹⁹ in ligand L-21        can be joined together to form a hydrocarbon ring or hetero        ring;    -   R²⁷═H, D, or F;    -   R²⁸═H, D, F or aryl;    -   R²⁹═H, D, F, alkyl, or silyl; and    -   R³⁹═H, D, or F.

In some embodiments, Y is selected from the group consisting of Y-1, Y-2and Y-3

wherein:

-   -   R¹¹ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl;    -   R¹² is H, D, or F; and    -   R¹³ is the same or different at each occurrence and is selected        from the group consisting of alkyl and fluoroalkyl.

In some embodiments of the formulae, the alkyl and fluoroalkyl, groupshave 1-5 carbon atoms. In some embodiments, the alkyl group is methyl.In some embodiments, the fluoroalkyl group is trifluoromethyl. In someembodiments, the aryl group is phenyl.

In some embodiments, the complex is tris-cyclometallated and L=L-19 orL-20. In some embodiments, the complex is bis-cyclometallated and L=L-20or L-21.

In some embodiments of L-19, at least one of R²³ through R²⁶ is a C₁₋₅alkyl group. In some embodiments of L-19, at least one of R²⁷ throughR³⁹ is fluoro.

In some embodiments of L-20, R²³ through R²⁶ are H or D. In someembodiments of L-20, at least one of R²¹ and R²⁹ is a C₁₋₅ alkyl group.

In some embodiments of L-21, at least one of R²³ through R²⁶ is F. Insome embodiments of L-21, at least one of R²¹ and R²⁹ is a C₁₋₅ alkylgroup.

Examples of organometallic Ir complexes having orange emission colorinclude, but are not limited to:

The overall emission of white light can be achieved by balancing theemission of the three colors. In some embodiments, the weight ratio ofhost:(total dopant) is in the range of 10:1 to 1000:1. In someembodiments, the ratio is 10:1 to 100:1; in some embodiments, 20:1 to80:1. In some embodiments, the weight ratio of (first dopant):(seconddopant) is in the range of 1:1 to 100:1; in some embodiments, 5:1 to50:1; in some embodiments, 10:1 to 30:1. As described herein, the firstdopant has green emission color and the second dopant has emission colorin the red/orange region.

c. Other Layers

The materials to be used for the other layers of the luminaire describedherein can be any of those known to be useful in OLED devices.

The anode is an electrode that is particularly efficient for injectingpositive charge carriers. It can be made of, for example materialscontaining a metal, mixed metal, alloy, metal oxide or mixed-metaloxide, or it can be a conducting polymer, and mixtures thereof. Suitablemetals include the Group 11 metals, the metals in Groups 4, 5, and 6,and the Group 8-10 transition metals. If the anode is to belight-transmitting, mixed-metal oxides of Groups 12, 13 and 14 metals,such as indium-tin-oxide, are generally used. The anode may alsocomprise an organic material such as polyaniline as described in“Flexible light-emitting diodes made from soluble conducting polymer,”Nature vol. 357, pp 477 479 (11 Jun. 1992). At least one of the anodeand cathode should be at least partially transparent to allow thegenerated light to be observed.

The hole injection layer comprises hole injection materials. Holeinjection materials may be polymers, oligomers, or small molecules, andmay be in the form of solutions, dispersions, suspensions, emulsions,colloidal mixtures, or other compositions.

The hole injection layer can be formed with polymeric materials, such aspolyaniline (PANI) or polyethylenedioxythiophene (PEDOT), which areoften doped with protonic acids. The protonic acids can be, for example,poly(styrenesulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonicacid), and the like. The hole injection layer can comprise chargetransfer compounds, and the like, such as copper phthalocyanine and thetetrathiafulvalene-tetracyanoquinodimethane system (TTF-TCNQ). In oneembodiment, the hole injection layer is made from a dispersion of aconducting polymer and a colloid-forming polymeric acid. Such materialshave been described in, for example, published U.S. patent applications2004-0102577, 2004-0127637, and 2005-0205860, and published PCTapplication WO 2009/018009.

The hole transport layer comprises hole transport material. Examples ofhole transport materials for the hole transport layer have beensummarized for example, in Kirk-Othmer Encyclopedia of ChemicalTechnology, Fourth Edition, Vol. 18, p. 837-860, 1996, by Y. Wang. Bothhole transporting small molecules and polymers can be used. Commonlyused hole transporting molecules include, but are not limited to:4,4′,4″-tris(N,N-diphenyl-amino)-triphenylamine (TDATA);4,4′,4″-tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine (MTDATA);N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine(TPD); 4,4′-bis(carbazol-9-yl)biphenyl (CBP);1,3-bis(carbazol-9-yl)benzene (mCP);1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC);N,N′-bis(4-methylphenyl)-N,N′-bis(4-ethylphenyl)-[1,1′-(3,3′-dimethyl)biphenyl]-4,4′-diamine(ETPD); tetrakis-(3-methylphenyl)-N,N,N′,N′-2,5-phenylenediamine (PDA);α-phenyl-4-N,N-diphenylaminostyrene (TPS); p-(diethylamino)benzaldehydediphenylhydrazone (DEH); triphenylamine (TPA);bis[4-(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP);1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl]pyrazoline(PPR or DEASP); 1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB);N,N,N′,N′-tetrakis(4-methylphenyI)-(1,1′-biphenyl)-4,4′-diamine (TTB);N,N′-bis(naphthalen-1-yl)-N,N′-bis-(phenyl)benzidine (α-NPB); andporphyrinic compounds, such as copper phthalocyanine. Commonly used holetransporting polymers include, but are not limited to,polyvinylcarbazole, (phenylmethyl)polysilane, poly(dioxythiophenes),polyanilines, and polypyrroles. It is also possible to obtain holetransporting polymers by doping hole transporting molecules such asthose mentioned above into polymers such as polystyrene andpolycarbonate. In some cases, triarylamine polymers are used, especiallytriarylamine-fluorene copolymers. In some cases, the polymers andcopolymers are crosslinkable. Examples of crosslinkable hole transportpolymers can be found in, for example, published US patent application2005-0184287 and published PCT application WO 2005/052027. In someembodiments, the hole transport layer is doped with a p-dopant, such astetrafluorotetracyanoquinodimethane andperylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride.

The electron transport layer can function both to facilitate electrontransport, and also serve as a buffer layer or confinement layer toprevent quenching of the exciton at layer interfaces. Preferably, thislayer promotes electron mobility and reduces exciton quenching. Examplesof electron transport materials which can be used in the optionalelectron transport layer, include metal chelated oxinoid compounds,including metal quinolate derivatives such astris(8-hydroxyquinolato)aluminum (AlQ),bis(2-methyl-8-quinolinolato)(p-phenylphenolato) aluminum (BAlq),tetrakis-(8-hydroxyquinolato)hafnium (HfQ) andtetrakis-(8-hydroxyquinolato)zirconium (ZrQ); and azole compounds suchas 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD),3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ), and1,3,5-tri(phenyl-2-benzimidazole)benzene (TPBI); quinoxaline derivativessuch as 2,3-bis(4-fluorophenyl)quinoxaline; phenanthrolines such as4,7-diphenyl-1,10-phenanthroline (DPA) and2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (DDPA); and mixturesthereof. In some embodiments, the electron transport layer furthercomprises an n-dopant. N-dopant materials are well known. The n-dopantsinclude, but are not limited to, Group 1 and 2 metals; Group 1 and 2metal salts, such as LiF, CsF, and Cs₂CO₃; Group 1 and 2 metal organiccompounds, such as Li quinolate; and molecular n-dopants, such as leucodyes, metal complexes, such as W₂(hpp)₄ wherehpp=1,3,4,6,7,8-hexahydro-2H-pyrimido-[1,2-a]-pyrimidine andcobaltocene, tetrathianaphthacene,bis(ethylenedithio)tetrathiafulvalene, heterocyclic radicals ordiradicals, and the dimers, oligomers, polymers, dispiro compounds andpolycycles of heterocyclic radical or diradicals.

The cathode, is an electrode that is particularly efficient forinjecting electrons or negative charge carriers. The cathode can be anymetal or nonmetal having a lower work function than the anode. Materialsfor the cathode can be selected from alkali metals of Group 1 (e.g., Li,Cs), the Group 2 (alkaline earth) metals, the Group 12 metals, includingthe rare earth elements and lanthanides, and the actinides. Materialssuch as aluminum, indium, calcium, barium, samarium and magnesium, aswell as combinations, can be used. Li-containing organometalliccompounds, LiF, Li₂O, Cs-containing organometallic compounds, CsF, Cs₂O,and Cs₂CO₃ can also be deposited between the organic layer and thecathode layer to lower the operating voltage. This layer may be referredto as an electron injection layer.

The choice of materials for each of the component layers is preferablydetermined by balancing the positive and negative charges in the emitterlayer to provide a device with high electroluminescence efficiency.

In one embodiment, the different layers have the following range ofthicknesses: anode, 500-5000 Å, in one embodiment 1000-2000 Å; holeinjection layer, 50-2000 Å, in one embodiment 200-1000 Å; hole transportlayer, 50-2000 Å, in one embodiment 200-1000 Å; photoactive layer,10-2000 Å, in one embodiment 100-1000 Å; electron transport layer,50-2000 Å, in one embodiment 100-1000 Å; cathode, 200-10000 Å, in oneembodiment 300-5000 Å. The desired ratio of layer thicknesses willdepend on the exact nature of the materials used.

The OLED luminaire may also include outcoupling enhancements to increaseoutcoupling efficiency and prevent waveguiding on the side of thedevice. Types of light outcoupling enhancements include surface films onthe viewing side which include ordered structures like e.g. microspheres or lenses. Another approach is the use of random structures toachieve light scattering like sanding of the surface and or theapplication of an aerogel.

The OLED luminaires described herein can have several advantages overincumbent lighting materials. The OLED luminaires have the potential forlower power consumption than incandescent bulbs. Efficiencies of greaterthan 50 Im/W may be achieved. The OLED luminaires can have Improvedlight quality vs. fluorescent. The color rendering can be greater than80, vs that of 62 for fluorescent bulbs. The diffuse nature of the OLEDreduces the need for an external diffuser unlike all other lightingoptions.

In addition, the OLED luminaires described herein have advantages overother white light-emitting devices. The structure is much simpler thandevices with stacked electroluminescent layers. It is easier to tune thecolor. There is higher material utilization than with devices formed byevaporation of electroluminescent materials. It is possible to use anytype of electroluminescent material, including electroluminescentpolymers.

4. Process

The process for making an OLED luminaire, comprises:

providing a substrate having a first electrode thereon;

depositing a liquid composition comprising a liquid medium havingdispersed therein a host material capable of electroluminescence havingblue emission color, a first electroluminescent dopant having greenemission color, and a second electroluminescent dopant having emissioncolor in the red/orange region;

drying the deposited composition to form an electroluminescent layer;and

forming a second electrode overall.

As used herein, the term “dispersed” indicates that theelectroluminescent materials are evenly distributed throughout theliquid medium. The liquid medium having electroluminescent materialsdispersed therein can be used to form continuous films. The liquidmedium having electroluminescent materials dispersed therein can be inthe form of a solution, emulsion, or colloidal dispersion.

Any known liquid deposition technique can be used, including continuousand discontinuous techniques. Examples of continuous liquid depositiontechniques include, but are not limited to spin coating, gravurecoating, curtain coating, dip coating, slot-die coating, spray coating,and continuous nozzle coating. Examples of discontinuous depositiontechniques include, but are not limited to, ink jet printing, gravureprinting, and screen printing.

Any conventional drying technique can be used, including heating,vacuum, and combinations thereof. In some embodiments, the drying stepresults in a layer that is partially dried. In some embodiments, thedrying step results in a layer that is essentially completely dried.Further drying of the essentially completely dried layer does not resultin any further device performance changes. In some embodiments, thedrying step is a multi-stage process. In some embodiments, the dryingstep has a first stage in which the deposited composition is partiallydried and a second stage in which the partially dried composition isessentially completely dried.

In some embodiments, the process uses as a substrate a glass substratecoated with ITO. Slot-die coating can be used to coat a hole injectionlayer from aqueous solution, followed by a second pass through aslot-die coater for a hole transport layer. The electroluminescent layercan also be deposited by slot die coating. The slot-die process stepscan be carried out in a standard clean-room atmosphere. Next the deviceis transported to a vacuum chamber for the deposition of the electrontransport layer and the metallic cathode. This is the only step thatrequires vacuum chamber equipment. Finally the whole luminaire ishermetically sealed using encapsulation technology, as described above.

Note that not all of the activities described above in the generaldescription are required, that a portion of a specific activity may notbe required, and that one or more further activities may be performed inaddition to those described. Still further, the order in whichactivities are listed are not necessarily the order in which they areperformed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

It is to be appreciated that certain features are, for clarity,described herein in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, reference to values stated in ranges include each and everyvalue within that range.

What is claimed is:
 1. An organic light-emitting diode luminaire comprising a first electrode, a second electrode, and an electroluminescent layer therebetween, the electroluminescent layer comprising: a host material capable of electroluminescence having an emission color that is blue; a first electroluminescent dopant having an emission color that is green, wherein the first electroluminescent dopant is an organometallic complex of Ir; and a second electroluminescent dopant having an emission color that is in a red/orange region, wherein the second electroluminescent dopant is an organometallic complex of Ir; wherein the additive mixing of the three mission colors results in an overall emission of white light; wherein the weight ratio of host: (total dopant) is in the range of 10:1 to 1000:1; wherein the weight ratio of (first dopant):(second dopant) is in the range of 1:1 to 100:1; and wherein the triplet energy of the host is high enough so that it does not quench the emission from the organometallic electroluminescent dopants.
 2. The luminaire of claim 1, wherein the host material is a tris-cyclometallated complex having the formula IrL₃ or a bis-cyclometallated complex having the formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has a formula selected from the group consisting of Formula L-1 through Formula L-12:

where: R¹ through R⁸ are the same or different and are selected from the group consisting of H, D, electron-donating groups, and electron-withdrawing groups, and R⁹ is H, D or alkyl; and * indicates a point of coordination with Ir.
 3. The luminaire of claim 2, wherein: R¹ is H, D, F, or alkyl; R² is H, D or alkyl; R³═H, D, F, alkyl, OR¹⁰, NR¹⁰ ₂; R⁴═H or D; R⁵═H, D or F; R⁶═H, D, F, CN, aryl, fluoroalkyl, or diaryloxophosphinyl; R⁷═H, D, F, alkyl, aryl, or diaryloxophosphinyl; R⁸═H, D, CN, alkyl, fluoroalkyl; R⁹═H, D, aryl or alkyl; and R¹⁰=alkyl, where adjacent R¹⁰ groups can be joined to form a saturated ring.
 4. The luminaire of claim 1, wherein the first electroluminescent dopant with green emission color is a tris-cyclometallated complex having the formula IrL₃ or a bis-cyclometallated complex having the formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has a formula selected from the group consisting of L-1, L-3 through L-7, and L-9 through L-17:

where: R¹ through R⁸ are the same or different and are selected from the group consisting of H, D, electron-donating groups, and electron-withdrawing groups, and R⁹ is H, D, or alkyl; and * represents a point of coordination with Ir.
 5. The luminaire of claim 4, wherein: R¹═H, D or F; R²═H, D, F, or alkyl; R³═H, D or diarylamino; R⁴═H, D or F; R⁵═H, D or alkyl, or R⁴ and R⁵ may be joined together to form a 6-membered aromatic ring; R⁶═H, D, CN, F, aryl, fluoroalkoxy, N-carbazolyl, diphenyl-N-carbazolyl or

R⁷═H, D, F, fluoroalkoxy, N-carbazolyl, or diphenyl-N-carbazolyl; R⁸═H, D or F; and R⁹═H, D, aryl or alkyl.
 6. The luminaire of claim 1, wherein the second electroluminescent dopant has red emission color and is a tris-cyclometallated complex having the formula IrL₃ or a bis-cyclometallated complex having the formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has a formula selected from the group consisting of Formula L-18, L-19 and L-20:

where: R¹ through R⁶ and R²¹ through R³⁰ are the same or different and are selected from the group consisting of H, D, electron-donating groups, and electron-withdrawing groups; and * represents a point of coordination with Ir.
 7. The luminaire of claim 6, wherein: R¹ through R⁴ and R²¹ through R²⁶ are the same or different and are H, D, alkyl, alkoxy, or silyl, or R¹ and R², R² and R³ or R³ and R⁴ in L-18, or R²³and R²⁴ or R²⁴ and R²⁵ in L-19 and L-20 can be joined together to form a hydrocarbon ring or hetero ring; R²⁷═H, D, F, alkyl, silyl, or alkoxy; R²⁸═H, D, CN, alkyl, fluoroalkyl, fluoroalkoxy, silyl, or aryl; and R²⁹═H, D, F, CN, alkyl, silyl, alkoxy, fluoroalkoxy, or aryl R³⁰═H, D, CN, alkyl, fluoroalkyl, fluoroalkoxy, or silyl.
 8. The luminaire of claim 1, wherein the second electroluminescent dopant has red-orange emission color and is a tris-cyclometallated complex having the formula IrL₃ or a bis-cyclometallated complex having the formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has a formula selected from the group consisting of Formula L-18, L-19, L-20 and L-21:

where: R¹ through R⁶ and R²¹ through R³⁰ are the same or different and are selected from the group consisting of H, D, electron-donating groups, and electron-withdrawing groups; AND * represents a point of coordination with Ir.
 9. The luminaire of claim 8, wherein: R¹ through R⁴ and R²¹ through R²⁶ are the same or different and are H, D, alkyl, silyl, or alkoxy, or R¹ and R², R² and R³ or R³ and R⁴ in ligand L-18, or R²³ and R²⁴ or R²⁴ and R²⁵ in ligand L-19 and L-20, or R²³ and R²⁴, R²⁴ and R²⁵, or R²⁵ and R²⁶ can be joined together to form a hydrocarbon ring or hetero ring; R²⁷═H, D, alkyl, or silyl; R²⁸═H, D, alkyl, or silyl; R²⁹═H, D, alkyl, silyl, alkoxy, fluoroalkoxy, or aryl; and R³⁰═H, D, alkyl, or silyl.
 10. The luminaire of claim 1, wherein the second electroluminescent dopant has orange emission color and is a tris-cyclometallated complex having the formula IrL₃ or a bis-cyclometallated complex having the formula IrL₂Y, where Y is a monoanionic bidentate ligand and L has a formula selected from the group consisting of Formula L-18, L-19, L-20 and L-21:

where: R¹ through R⁶ and R²¹ through R³⁰ are the same or different and are selected from the group consisting of H, D, electron-donating groups, and electron-withdrawing groups; and * represents a point of coordination with Ir.
 11. The luminaire of claim 10, wherein: R¹ through R⁴ and R²¹ through R²⁶ are the same or different and are H, D, alkyl, or silyl, or R¹ and R², R² and R³ or R³ and R⁴ in ligand L-18, or R¹⁶ and R¹⁷ or R¹⁷ and R¹⁸ in ligand L-19 and L-20, or R¹⁶ and R¹⁷, R¹⁷ and R¹⁸, or R¹⁸ and R¹⁹ in ligand L-21 can be joined together to form a hydrocarbon ring or hetero ring; R²⁷═H, D, or F; R²⁸═H, D, F or aryl; R²⁹═H, D, F, alkyl, or silyl; and R³⁰═H, D, or F.
 12. The luminaire of claim 2, 4, 6, 8 or 10, wherein Y is selected from the group consisting of Y-1, Y-2 and Y-3

wherein: R¹¹ is the same or different at each occurrence and is selected from the group consisting of alkyl and fluoroalkyl; R¹² is H, D, or F; and R¹³ is the same or different at each occurrence and is selected from the group consisting of alkyl and fluoroalkyl.
 13. The luminaire of claim 1, wherein the weight ratio of host:(total dopant) is in the range of 20:1 to 80:1.
 14. The luminaire of claim 1, wherein the weight ratio of first dopant:second dopant is in the range of 5:1 to 50:1. 